In a sign of Detroit’s continuing challenges, the city’s schools, police stations, fire houses and other public buildings lost power Tuesday morning after an aging underground cable failed.

Within 90 minutes, the Detroit Public Lighting Department with help from
DTE Energy Co.
began restoring service, and all affected buildings had access to power by Tuesday evening, the city said.

The outage was most apparent in downtown Detroit, where many public buildings were closed for the day. Some people were trapped in elevators, while others milled about on the street, waiting to see if the power would come on. Others got into cars and jammed roads that lacked traffic signals. Schools closed early and some court trials were interrupted.

The Frank Murphy Hall of Justice is one of many public buildings in Detroit without power on Tuesday.
Detroit Free Press/Associated Press

It also served as a reminder of the city’s problems, even as it nears an exit from Chapter 9 bankruptcy protection. “The bankruptcy order doesn’t solve the decades of neglect in our infrastructure, and that is what we saw today,” said Mayor
Mike Duggan
in a news conference.

The problem started with the failure of an aging underground cable early Tuesday for reasons that aren’t clear, officials said. That triggered a malfunction in one circuit breaker and the shutdown of the entire system by a second circuit breaker, which tripped to prevent damage to more equipment.

Lights flickered in structures around the city and went dead at about 10:30 a.m. The outage affected public courts, city hall, the convention center and sporting arenas, as well as fire houses, schools and police stations.

The city-run Public Lighting Department provides power to 890 public buildings—although some, like hospitals and a few fire stations, have backup generators.

The Michigan State Police dispatched 18 troopers to help with traffic control, officials said, joining about 78 Detroit police officers.

Under Detroit’s bankruptcy plan, the Public Lighting Department eventually will be folded into DTE Energy, a large investor-owned utility serving residential and commercial customers in Detroit and other parts of Michigan.

DTE spokesman
Scott Simons
said the utility is in the process of assessing the condition of the municipal network to prioritize needed upgrades. He said it could take five to seven years to transfer all customers to DTE’s system.

“Public Lighting is an antiquated system, and because of the city’s financial situation, it’s been neglected,” he said. “It needs to come up to our standards.”

Mr. Duggan said DTE is spending about $200 million on the project. This summer, DTE began working on parts of the system that repeatedly have failed, including equipment that caused numerous school closings last year, the mayor said, adding that there hadn’t been any school closures because of power failures this fall until now.

Detroit Public Schools said they switched to a half-day schedule Tuesday because of the outage. The mayor said the city transportation department scrambled 20 buses to help take children home early.

After decades of decline, the city entered bankruptcy protection last year and hopes to officially emerge soon. A federal bankruptcy judge last month approved the Motor City’s restructuring plan, which will slash some $7 billion off its $18 billion debt load.

The mayor said the crisis shows how much work still needs to be done for the city to recover.

Across from Wayne State University, which was without power much of the day, Great Lakes Coffee Roasting Co. was exceptionally crowded after the outage began.

“We’ve had power, and we’ve been busy,” said
Andrew Hansen,
the coffee shop’s general manager. “We’ve probably had 30 or 40 calls from customers asking if we’ve got power.”

The only problem is the crowds are mostly students looking for a place to do homework and not necessarily spend money. “It hasn’t really upped our sales, but it’s upped our chaos,” he said.